Substituted butadiene and hexatriene photosensitizers

ABSTRACT

A novel class of compounds is disclosed of the formula   WHEREIN R1 and R2 are lower-alkoxy or di(lower-alkyl)amino and R2 can be hydrogen and R3 and R4 are hydrogen, lower-alkoxy or di(lower-alkyl)amino and n is an integer from 1 to 5. The compounds are sensitizers for photosensitive compounds particularly polymers containing sulfonazido groups as the lightsensitive moiety.

United States Patent 1191 1111 3,879,463

Peters, Jr. et al. Apr. 22, 1975 SUBSTITUTED BUTADIENE AND Heitman etaL, Chemical Abstracts, Vol. 59, p.

HEXATRIENE PHOTOSENSITIZERS 9854C (1963).

Jutz et al.,-Chemisch Berichty" Vol. 102, pp. 623-6 [75] Inventors:Gerret M. Peters, Jr., Menden; Fred l 969).

A. Stuber, North Haven; Henri Ulrlch, Northford, all of Conn. 1 13214(1963).

[ Assignee: h Upjohn Company Kalamazoo Bahner et al., ChemicalAbstracts," Vol. 71, abs. No.

Mlch. 29l3lv (1969).

[22] Filed: May 10, 1973 Primary Examiner-Elbert L. Roberts [211 App!359132 Assistant E.\'aminerS. P. Williams Attorney, Agent, or Firm-DenisA. Firth; John Kekich [52] US. Cl. 260/571; 260/57l; 260/574;

260/576; 260/945; 260/951; 260/961; [57] ABSTRACT 260/600; 260/612 R;260/613 R [51] Int CL C07c 93/14; C07c 87/50; C07: 43/20 A novel classof compounds 1s disclosed of the for Schmiechen et 2]., ChemicalAbstracts," Vol. 59, pp. 7

[58] Field of Search 260/576, 571 mula [56] References Cited wherein Rand R are lower-alkoxy or di(lower- UNITED STATES PATENTS alkyl)amin0and R can be hydrogen and R and R are hydrogen, lower-alkoxy ordi(lower-alkyl)amin0 5:2 5: 3 and 11 is an integer from 1 to 5. Thecompounds are 3658 703 1/1971 Adam et ni /1:1..."I: 260/571 x sensitizefor phmosensitive compounds Particularly polymers containing sulfonazidogroups as the light- OTHER PUBLICATIONS Sensitive moiety 1 Syz et al.,Helvetica Chimica Acta, Vol. 48(3), pp.

5l7, 521, & 523 (1965). 3 Claims, No Drawings SUBSTITUTED BUTADIENE ANDI-IEXATRIENE PHOTOSENSITIZERS BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention relates to novel polymers and is moreparticularly concerned with a,m-diaryl polyenes and with methods fortheir preparation and methods for their use as photosensitizers.

2. Description of the Prior Art To the best of our knowledge thecompounds of the invention are novel. Nuclear unsubstituted a,w-diarylpolyenes e.g. 1,4-diphenyl butadiene, are well-known in the art but showno ability to act as photosensitizers when used in the context describedhereinafter.

SUMMARY OF THE INVENTION The invention comprises compounds of theformula:

in R wherein R is selected from the group consisting of hydrogen,lower-alkoxy and di(lower-alkyl)amino, R is selected from the groupconsisting of lowcr-alkoxy and di(lower-alkyl)amino, and R and R areindependently selected from the group consisting of hydrogen,loweralkoxy and di(lower alkyl)amino, and n is an integer 1 I C..-CH-CH-CH ..W

wherein n, R R R and R are as hereinbefore defined, and R and Rrepresent lower-alkyl.

The reaction of the unsaturated aldehyde (II) and the benzylphosphonate(III) is carried out advantageously by bringing the reactants togetherin the presence of a strong base and an inert organic solvent. Examplesof strong bases are sodium hydride, potassium hydride, lithium hydride,sodamide, sodium ethoxide, potassium tert-butoxide and the like. Theterm inert organic solvent means an organic solvent which is inert underthe conditions of the reaction i.e. does not enter into or interferewith the desired course of the reaction. Examples of inert organicsolvents are dimethoxyethane, benzene, toluene, xylene, hexane, heptane,tetrahydrofuran, dimethylformamide, and the like.

The reactants (II) and (III) are employed in approximatelystoichiometric proportions. The reaction is preferably carried out atelevated temperature within the range of about 60C to about 85C. Thecourse of the reaction is followed by routine procedures e.g. byspectroscopic analysis of aliquots, and when the reaction is judged tobe complete the desired polyene (I) is isolated therefrom by procedureswell-known in the art. For example, the solvent can be removed bydistilfrom 1 t lation and the residue purified by recrystallization,

The term y means alkyl from 1 to 6 chromatography, fractionalprecipitation and like techbon atoms, inclusive, such as methyl, ethyl,propyl, buniques y P y y and iSQmeric forms thereof The term Theunsaturated aldehydes (II) and the benzylphos- 'f if means alkoxy from 1to 6 carbon phonates (III) which are employed as starting materialsatoms, mcluslve, Such as methoxy, eihoxyi P P Y 40 in the preparation ofthe compounds of the invention butoxy, Pemyioxy, hexyloxy and Somencforms are for the most part known in the art and are prepared thereofbyknown techniques. For example the unsaturated al- The Compounds of themvefltlon are usefu! as dehydes (II) can be prepared by condensation ofthe sensitizers and are more particularly useful insensitizcorresponding substituted benzaldehydes ing light-sensitivepolymers containing sulfonylazide groups to radiation of wavelengths towhich said polymers are not normally sensitive. These uses will bediscussed in more detail hereafter. R DETAILED DESCRIPTION OF THEINVENTION 5O CHOI The novel compounds of the formula (I) areconveniently prepared by the method which is illustrated 2 schematicallyas follows:

R1 0 R3 0 1 Rs icr1=cH CHO P-- CH 1 n R 0 I R 4 (II) (III) p v C 0 s 0 tI P- OH CH2 c1,

wherein R and R are as hereinbefore defined, with elimination oflower-alkyl chloride, in accordance with the procedures well-known inthe art for the preparation of phosphonates.

The compounds of the invention of the formula (I) find particular use assensitizers for light-sensitive material. In particular, it has beenfound that the compounds of formula (I) can be used to sensitizelightsensitive polymers containing sulfonylazide groups to radiation ofwavelengths which do not normally activate such polymers. For example,the sulfonylazidocontaining light sensitive polymers which are describedin copending application Ser. No. 93,446, file Nov. 27, 1970 in thenames of Adnan A. R. Sayigh, Fred A. Stuber and Henri Ulrich, arederived by reacting copolymers of maleic anhydride and styrene, orcopolymers of maleic anhydride and methyl vinyl ether, with ahydroxyalkyl azidosulfonyl carbanilate. This results in opening of theanhydride moieties of the starting copolymer to give recurring unitshaving a free carboxy group and an esterified carboxy group containing asulfonylazide group in the ester moiety. These light sensitive polymersare useful, amongst other things, in the preparation of continuous toneimages, in rendering hydrophilic the surface of substrates to which saidpolymers can be bonded by exposure to suitable radiation, and in thepreparation of photoresists.

However, said light sensitive polymers, when used without sensitizers,are activated by light of wavelength about 260 to 300 nm, i.e. in theultraviolet spectrum. This means that special, and relatively expensive,sources of radiation need to be used in conjunction with these polymers.It has accordingly become desirable to sensitize said polymers in such amanner that they can be activated by radiation in the wavelengths of theorder of 400-500 nm so that much cheaper and more readily accessiblesources of radiation e.g. tungsten lamps, could be used.

The use of the compounds of formula (I) has made it possible tosensitize said light-sensitive polymers in the desired manner so as torender them activatable by radiation in the range of 400-500 nm. Inusing the compounds of the formula (I) as sensitizers it is merelynecessary to incorporate them into the composition in which thelight-sensitive polymer is applied to the substrate. In general thelight-sensitive polymer is applied to the substrate in the form of afilm by use of a solution of the light-sensitive polymer in a suitablesolvent such as acetone, acetonitrile, methyl ethyl ketone and the like.In this case the sensitizer of formula (I) is incorporated into asolution of the light-sensitive polymerbedimethylaminobenzylphosphonate,

fore said solution is applied to the substrate. Advantageously thesensitizer of formula (I) is employed in a proportion of about 10 partsto about 20 parts by weight per parts of light-sensitive polymer.

The above findings are all the more surprising in view of the fact thatthe closely related compound, l,4-diphenyl-l,3-butadiene shows nosensitizing properties when employed under identical conditions to thosedescribed above.

The following preparation and examples describe the manner and processof making and using the invention and set forth the best modecontemplated by the inventors of carrying out the invention but are notto be construed as limiting.

PREPARATION l.

0,0-diethyl 2,5-dimethoxybenzylphosphate A mixture of 3.5 g (18.8 mmole)of 2,5- dimethoxybenzyl chloride (Kost et al., Zh. Obshch. Khim, 33,2011, 1963; Chemical Abstracts 62, 16089h, 1965) and 25 g. (150 mmole)of triethylphosphite (previously dried over metallic sodium) was heatedunder reflux for 24 hours. The resulting mixture was subjected tofractional distillation under reduced pressure. After removal of excesstriethylphosphite the fraction which distilled at to 147C. at a pressureof less than 1 mm. of mercury was collected. There was thus obtained0,0-diethyl 2,5-dimethoxybenzylphosphonate in the form of a colorlessliquid which exhibited a bluish fluorescence when exposed to ultravioletlight. The nmr spectrum was in agreement with the assigned structure.

Similarly, using the above procedure, but replacing 2,5-dimethoxybenzylchoride by 4- dimethylaminobenzyl chloride, 3-methoxy-4-dimethylaminobenzyl chloride, or 3-methoxybenzyl chloride, there wereobtained 0,0-diethyl 4- 0,0-diethyl 3-methoxy-4-dimethylaminobenzylphosphonate and 0,0- diethyl3-methoxybenzylphosphonate, respectively.

PREPARATION 2.

Using the procedure described by Konig et al., supra, for thepreparation of 4- dimethylaminocinnamaldehyde but replacing the 4-dimethylaminobenzaldehyde employed as starting material by2,S-dimethoxybenzaldehyde, there was obtained2,5-dimethoxycinnamaldehyde.

EXAMPLE 1 1 2,5 -dimethoxyphenyl )-4-(4- dimethylaminophenyl)-butadiene.

To a mixture of 5 g. (28.5 mmoles) of 4- dimethylaminocinnamaldehyde(Konig et al, supra) and 8.2 g. (28.5 mmole) of 0,0-diethyl 2,5-dimethoxybenzylphosphonate (Preparation 1) in approximately 30 ml of1,2-dimethoxyethane was added 0.7 g. (29 mmoles) of sodium hydride. Theresulting mixture was heated under reflux for 90 minutes. The mixturewas cooled to room temperature, the supernatant liquor was decanted fromthe orange gummy material which had settled out and the latter waswashed with circa 50 ml. of 1,2-dimethoxyethane. The washings and thesupernatant were combined and concentrated to about 60 ml. byevaporation before being poured into circa 300 ml. of water. The solidmaterial which separated was isolated by filtration and recystallizedfrom ethanol. There was thus obtained 2.7 g. of

l-(2,5-dimethoxyphenyl)-4-(4-dimethylaminophenyl butadiene in.the formof a crystalline solid having a melting point of 118 to 120C. The UVspectrum of this material (2 X molar solution in acetonitrile) exhibiteda maximum at 380 nm (e =49,500). The nuclear magnetic resonance spectrumwas also in accordance with the assigned structure.

In order to assess the efficiency of the above compound in extending thesensitivity of a sulfonylazide photosensitive polymer to radiation ofwavelength of the order of 400 nm. the following experiments werecarried out.

A solution of 2.2 parts by weight of Photozid (a lightsensitivesulfonylazide polymer obtained by reacting a maleic anhydride vinylmethyl ether copolymer with 2-hydroxyethyl 4-azidosulfonylcarbanilate;The Upjohn Company) and 0.22 parts by weight of the above butadiene in100 parts of methyl ethyl ketone was used to whirler cast films oflight-sensitive polymer on strips of Mylar. Individual coated Mylarstrips were then exposed, via a negative image comprising a pattern ofdots, to radiation of wavelengths 400 nm., 404 nm. and 435 nm. (producedby use of appropriate filters which excluded all other frequencies fromthe radiation produced by an Osram XBO 150 watt high pressure Xenonlamp.) The exposure times were 30 seconds for 400 nm. wavelength, 3minutes for the 404 nm. and 10 minutes for the 435 nm. radiation. Afterexposure the irradiated Mylar strips were developed by immersion for 60seconds in a bath containing a mixture of 5 parts of methyl ethyl ketoneand 1 part of 4-methyl-2- pentanone. The developed strips were then dyedby immersion for 60 seconds in a 1 percent w/w aqueous solution of BasicBlue 9. A clear blue image was achieved on all test strips. In contrast,strips which were prepared and irradiated in exactly the same manner buteither omitting the butadiene from the initial polymer solution orreplacing said butadiene by an equal weight of 1,4-diphenyl butadiene,showed no image thus indicating that, in the absence of the abovebutadiene sensitizer or when said butadiene was replaced by 1,4-diphenylbutadiene, the Photozid had not been activated by the radiationof the above wavelengths.

EXAMPLE 2 Using the procedure described in Example 1, but replacing4-dimethylaminocinnamaldehyde by 1-(4-dimethylaminophenyl)-l,3-pentadien-5-al (Jutz, supra) there was obtainedl-(2,5-dimethoxyphenyl)-6- (4-dimethylaminophenyl)-1,3 ,5-hexatriene.

Similarly, using the procedure described in Example 1, but replacing4-dimethylaminocinnamaldhyde by l- (4-dimethylaminophenyl)- l,3,5-heptatrient-7-al, there was obtained1-(2,5-dimethoxyphenyl)-8-(4-dimethylaminophenyl)1,3,5,7octatetraene.

EXAMPLE 3.

Using the procedure described in Example 1, but replacing 0,0-diethyl2,5-dimethoxybenzylphosphonate by 0,0-diethyl3-methoxy-4-dimethylaminobenzylphosphonate or 0,0-diethyl3-methoxybenzylphosphonate, there were obtained: 1-( 3-methoxy-4-dimethylaminophenyl)-4-(4-dimethylaminophenyl)- butadiene, and l-(3-methoxyphenyl )-4-(4-dimethylaminophenyl)butadiene, respectively.

EXAMPLE 4.

Using the procedure described in Example 1, but replacing the4-dimethylaminocinnamaldehyde there used by 2,5-dimethoxycinnamaldehyde,there was obtained l,4-di(2,5-dimethoxyphenyl)butadiene.

Similarly, using the procedure described in Example 1, but replacing4-dimethylaminocinnamaldehyde by 4-ethoxy-3-methoxycinnamaldehyde (J.Amer.

Chem. Soc. 72, 2501, 1950) 4-methoxycinnamaldehyde (J. Chem. Soc. 1956,

4082) l-(4-methoxyphenyl)-l ,3-pentadien-5-al (ibid)l-(4-methoxyphenyl)-l,3,5-heptatrien-7-al (ibid) or 1-(4-methoxyphenyl)-l ,3,5,7-nonatetraen-9-al, there were obtained:

l-( 2,5-dimethoxyphenyl )-4-(4-ethoxy-3-methoxyphenyl)butadiene,l-(2,5-dimethoxyphenyl)-4-(4-methoxyphenyl)- butadiene,l-(2,5-dimethoxyphenyl)-6-(4-methoxyphenyl- 1 ,3,5-hexatriene, 1-( 2,S-dimethoxyphenyl )-8-( 4-methoxyphenyl l,3,5,7-octatetraene, and1-(2,5-dimethoxyphenyl)-l0-(4-methoxyphenyl)- 1,3,5,-7,9-decapentaene,respectively.

EXAMPLE 5.

l ,4-di(4-dimethylaminophenyl)-1,3-butadiene To a mixture of 5 g. (18.4mmoles) of 0,0-diethyl 4- dimethylaminobenzylphosphonate (Preparation 1)and 3.2 g. (18.4 mmoles) of 4- dimethylaminocinnamaldehyde in 40 ml. of1,2- dimethoxyethane was added 0.6 g. (25 mmole) of sodium hydride. Theresulting mixture was heated under reflux for 2.25 hours. At the end ofthis period the mixture was cooled and poured into 300 ml. of coldwater. The orange-tan solid which separated was extracted withchloroform and the chloroform extract was dried over anhydrous sodiumsulfate. The dried extract was evaporated to dryness and the residue wasrecrystallized from ethanol. There was thus obtained l,4-di(4-dimethylaminophenyU-l ,3-butadiene in the form of an orange yellow solidhaving a melting point of 234to 240C. The ultraviolet spectrum of thismaterial (acetonitrile) exhibited a maximum at 385 nm (e 72,200). Thenuclear magnetic resonance spectrum was also in accordance with theassigned structure.

The above compound was then used to sensitize Photozid according to theprocedure described at the end of Example 1, supra. It was found that aclear blue image was obtained using radiation of wavelength 435 EXAMPLE6.

1-( 2,5-dimethoxyphenyl )-4 -phenyl-l ,3-butadiene To a mixture of 10 g.(76 mmole) of cinnamaldehyde and 22 g. (76 mmole) of 0,0-diethyl2,5-dimethoxybenzylphosphonate (Preparation 1) in 60 ml. of freshlydistilled 1,2-dimethoxyethane was added 2 g. (76 mmole) of sodiumhydride. The resulting mixture was heated under reflux for 3 hours. Atthe end of this time the reaction mixture was cooled and filtered toremove a yellow solid. The filtrate was diluted with water and extractedwith chloroform. The chloroform extract was dried over anhydrousmagnesium sulfate and the dried extract was evaporated to dryness. Therewas thus obtained 16 g. of l(2,5-dimethoxyphenyl)-4-phenyl-l ,3-butadiene in the form of an orange yellow viscous liquid. A sample (4.1g.) of this material was purified by dissolving in benzene andsubjecting to chromatograoca (CH CH) ocn wherein n is an integer from 2to 3.

2. l-( 2,5-dimethoxyphenyl )-4-(4-dimethylamin0- phenyl )-l,3-butadiene.

3. l-(2,5-dimethoxyphenyl)-6-(4-dimethylaminophenyl) 1 ,3,5-hexatriene.

1. A COMPOUND HAVING THE FORMULA:
 1. A compound having the formula: 2.1-(2,5-dimethoxyphenyl)-4-(4-dimethylaminophenyl)-1,3-butadiene.